1. Field of the Invention This invention relates to new, porous forms of textiles and includes processes for making such textiles. These new textiles may be used for reinforcing roofinq membranes, carpets, tarpaulins and other purposes. The products of this invention can have increased absorptive properties and individual yarn porosity. The products of this invention further can have good flexibility and provide easier processing on less complicated manufacturing equipment. For example, the use of the product of this invention in the manufacture of roofing membranes is less likely to lead to wrinkles, creases or other structural defects than products made from the same yarn but without the resin and interstices of this invention.
2. Description Of The Prior Art
Reinforcing composites for bitumenous roofing membranes, such as described in commonly assigned U.S. Pat. Nos. 4,491,617 and 4,539,254, have been made using combinations of scrims and light weight non woven mats. The scrims provide strength and the light-weight non-woven mats provide for ease of saturation of the bitumen. The art also uses heavy polyester mats (for example, 170 grams per square yard or more) without any reinforcing scrim. These heavy mats, however, are needle punched to provide porosity for saturation. Not only do such heavy mats require a great deal of polyester per square yard, but they do not have as great tear resistance or ease of saturation as is desired. Attempts to use weft-inserted warp-knit polyester scrims (6.times.6 yarns per inch or 9.times.9 yarns per inch of 1000 denier continuous filament polyester) without any mat have provided excellent strength, elongation, tear resistance, and heat stability in roofing membranes of bitumen but have been unacceptable due to low stiffness, poor adhesion to the bitumen and excessively thin gauge (for example, 9 mils, 230 microns).
In the field of carpets, primary backings commonly made of jute receive tufts of carpet yarn which are held by mechanical forces and friction (i.e. mechanical adhesion) and extend from one side of the primary backing. This combination is then attached to the top of a resilient backing such as latex foam. Various synthetic, non-woven primary backings have also been used instead of jute. Attempts to use polyester fabrics of 6.times.6 or 9.times.9 yarns per inch of 1000 denier yarn in primary backings without any mat have been unsuccessful because they have given neither sufficient coverage nor sufficient mechanical adhesion to hold carpet tufts.